Hi Forum folk.
Heres where I am at:
1991 Honda Accord Wagon EX w/ 2-2 Liter Engine.

Problem:

Engine has rough idle with slight (5-150 rpm) intermittent/occasional hunting of the RPM.

Check engine light comes on only at highway speeds and only after about 10 minutes at speeds greater than 70 km.

Often before the check engine light comes on the engine will stumble and stutter and refuse to accelerate while in the 60-70 km range. Immediately the check engine light comes on, the engine accelerates normally.

OBD code is 43 - Fuel System Supply



Corrective actions taken:

Downstream O2 sensor replaced

Gasoline Filter replaced

Spark plugs replaced w/ recommend brand

Distributor cap removed and all visible components cleaned

EGR Valve removed, cleaned and diaphragm tested

IACV valve removed and cleaned

Fast Idle Speed Valve cleaned and adjusted (cold idle speed functions normally)

EGR manifold ports - plugs removed and manifold cleaned

Fuel system pressure tested by opening fuel rail inlet and cranking engine

PCV Valve cleaned and checked

I am lacking any sophisticated diagnostic tools and I am ready to go to my favorite mechanic and pay dearly, but before I do any ideas??
Rickweath

 

this is a really tricky code, if it were me I would pull a new set of injectors from a junkyard car along with an ecu

 

Hi, Thanks for the advice. I wish I could disagree with your ecu and injector replacement idea but it's not practical where I live. Keeping in mind this vehicle is fairly rare there are not a lot of auto wreckers around wth reliable used Honda parts. I suppose it may come down to this but maybe for now I am better off paying for some professional diagnostics. If indeed you are right then I will go online to vancouver or elswhere to see what I can find. My worry is if the used parts are any good.

 

this code is generated when the ecu can't compensate for air fuel mixtures to bring it to optimal

it can be a variety of things, normally it's the oxygen sensor, but it can be a number of things, I would say ecu is the number 2 cause

the only reason i suggested replacing the ecu and the injectors is cause you replaced most components already

i would guesstimate your issue is either the ecu or an exhaust leak..you can try seafoaming through the brake booster on a cold start when the car is idling higher and look for an exhaust leak anywhere from the exhaust manifold to the oxygen sensor

 

Already had my mechanic check for an exhaust leak and all is well. You may very well be right about the ecu. I will check into this, thanks.

 

if you were saying that the car runs fine after it has thrown the code and check engine light is on it's even more likely the ecu is the cause, but it could just be that it's turning off a bad sensor

 

You are making a great deal of sense regarding the ECU. I will see if I can find a used one first. I would hate to see what a new one would cost but I will look on Amazon, eBay and a few other sources I have in mind.. Thanks again for your logic.

 

Although I'm not sure if it is as important as it was a few years ago, but the O2 sensor also has a recommended brand for these Hondas. Denso is that brand. Denso is also the OE part. People have reported problems with the Bosch brand O2 sensor; particularly the one that you have to wire the connector yourself.

 

Have you replaced the primary upstream O2 sensor? I see that you replaced the downstream O2. That rarely has anything to do with engine operation, it is more of a catalyst monitor.

As far as injectors go, you can use the injectors from any trim Accord from 90-95. Or any OBDI low impedance 240cc Honda injector for that matter. As far as the rareness of your Wagon, when it comes to the engine and ECU... you can use any Accord ECU for the 2.2L engine with corresponding transmission. Any PT3 or PT6 ECU will work. If you have the F22A6 the PT6 ECU would be the best option. F22A1 or A4 PT3.

 

 

You will have to excuse me, there are a few generations of Accords covered in this forum. When I read that you replaced the downstream O2, I assumed that it was a Honda that had both upstream and downstream O2 sensors. Now that I look back at the year of your Accord. Your PGM-FI only runs with 1 primary heated O2 sensor. Sorry

But yes, Denso or Nippon Denso or NGK/NTK are OEM replacement O2 sensors. Universal fit or Bosch sensors are hit and miss. Best to use an OEM replacement.

 

I should have said it was the upstream sensor. My mistake. It is the one right below the exhaust manifold. I cannot remember what the brand name was but I will have it checked. I fully understand that these sensor's that are not the same as the original can have problems. It is just another thing I agree has to be carefully checked.